Apparatus for casting metals



Apr, 17, 1923. 1,452;480

I -N.- K. B. PATCH APPARATUS FOR CASTING METALS Filed Dec. 6, 1920 2 Sheets-Sheet 1 Patented Apr. 17, 1923.

1,452,480 OFFICE.

NATHANIEL K. B. PATCH, OF BUFFALO, NEW YORK, ASSIGNOR T0 LUMEN BEARING COMPANY, OF BUFFALO, NEW YORK, A CORPORATION OF NEW YORK.

APPARATUS FOR CASTING- METALS.

Application filed December 6, 1920. Serial No. 428,452.

To all whom it may concern:

Be it known that I, NATHANIEL In. B.

PA'roir, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Apparatus for Casting Metals, of which the following is a specification.

This invention relates to a metal-casting apparatus designed more particularly for casting rings, gear-blanks, etc., of brass, bronze and other nonferrous alloys.

'Its principal object is the production of castings which are superior in strength, density and purity to castings produced under ordinary hydrostatic pressure.

In the acompanying drawings: Figure l is a top plan view of a novel apparatus in which the improved method may be practiced. Figure 2 is a vertical section on line 22, Fig. 1. Figure 3 is a bottom plan view of the core.

Similar characters of reference indicate corresponding parts throughout the several views.

The apparatus illustrated in the drawings comprises an upright shaft 10 carrying a head or table 11, and a mold generally designated by the reference numeral 12 and mounted on said table to rotate therewith. Rotary motion is imparted to this shaft by any appropriate means, not shown.

The moldin flask herein shown comprises a box or housing 14:, preferably of cast iron mounted on the table 11, so as to turn therewith, and having a cover 15 removably clamped thereon by swivel bolts 16 or other suitable fastenings. are a pair of superposed chills 17 and 18 having molding cavities 19 and 20 of the proper contour to form together a ring on the outer or rim portion of a gear-blank or similar annular object. Seated upon the bottom of the box 14: and within the lower chill 18 is a hollow block 21 of refractory material such as fire clay, carborundum or asbestos having a relatively deep and wide well or cavity 22 which communicates with the chill-cavitiesv 19, 20, and whose top is substantially level with the bottom of the cavity 20 of the lower chill. This block forms a refractory lining for the lower por- 14 and the part of the lower chill below the Arranged in this boxcore 23 of sand, metal or other suitable ma-- terial, provided in its center with a sprue 24 and in its underside with a plurality of gates or passages 25, preferably arranged radially at equidistant points of the core, through which gates the molten alloy poured into the flask flows into the cavities of the chills 17, 18. In the construction shown, the bore of the upper chill is flared upwardly, as shown at 26. and the contiguous upper end 26 of the core is correspondingly enlarged, to suspend it from said chill.

At or adjacent to the lower end of its sprue, the core is provided with an annular rim or trap 27 which preferably depends below the bottom of the cavity of the lower chill 18, as shown. This trap intercepts the dross and prevents it from entering the molding cavities of the chills.

In the use of the apparatus, after assembling the'chills and the core in the flask, the

cover 15 is applied and secured in place by.

the bolts 16. The flask is then rapidly rotated by means of the driving shaft 10 and the molten alloy is poured into it. The alloy is thrown outward into the cavities of the chills by centrifugal force and subjected to the resulting pressure, thus completely filling the mold, condensing the metal and producing a strong and dense casting of a high degree of purity.

By thus chilling the alloy under the pressure of centrifugal force, a better crystal growth is also obtained than under ordinary hydrostatic pressure.

If desired, the alloy may be poured into the flask before rotating it, instead of pouring the alloy while the flask is in motion.

, In this case, a charge of molten metal greater than is necessary to fill the chill cavities is poured into the mold while at rest,

to about the level of the bottom of the lower chill cavity 20. Upon first pouring the metal into the mold, the dross collects in the central cavity of the core 23 and is pocketed suming the form of an inverted cone of gradually increasing depth with the dross gathered at its apex. By the time the chill ca-v- =ities are filled, a part of the surplus metal closes the gates 25 and the remainder lies ,against the wall of the hollow block 21, while the dross collects on the inner side of the metal layer. Escape of the dross into the chill cavities is thus prevented during the initial operation by the trap 27 and during the remainder thereof by said surplus metal, producing a strong and dense casting which is free from dross on all sides and practically pure in all portions thereof,

The chills may be of sand, iron, copper or other metal, according to the extent or rapidity of the chilling effect desired.

claim as my invention:

1. An apparatus for casting metals under the pressure of centrifugal force, comprising a rotatable head, and a molding flask mounted on said head to rotate therewith, said flask having a molding cavity in its upper portion and a comparatively deep well for molten metal in its lower portion communicating with said molding cavity.

2. An apparatus for casting metals under the pressure of centrifugal force, comprising a rotatable head, and a molding flask mounted on said head to rotate therewith, said flask having a molding cavity in its upper portion and a comparatively deep well for molten metal in its lower portion "communicating with said moldingcavity,

said well being of greater capacity than said molding cavity, whereby the surplus metal thrown by centrifugal force against the wall of said well prevents the entrance of the dross into the molding cavity.

3. An apparatus for casting metals under the pressure of centrifugal force, comprising a, rotatable head, a molding flask mounted on said head to rotate therewith, said flask having a molding cavity in its upper portion and a comparatively deep well for molten metal in its lower portion communicating with said molding cavity, and a core arranged in said molding cavity and having a gate leading from said well to the molding cavity.

4;. An apparatus for casting metals under the pressure of centrifugal force, comprising a rotatable head, a molding flask mounted on said head to rotate therewith, said flask having a molding cavity in its upper portion and a comparatively deep well for molten metal in its lower portion communicating with said molding cavity, and a core arranged in said molding cavity and having a trap at its lower end to prevent the passage of the dross into said cavity and a gate leading from said well to said cavity.

5. An apparatus for casting metals under the pressure of centrifugal force, comprising a rotatable head, a molding flask mounted on said head to rotate therewith, a pair of superposed chills arranged in the flask and provided with molding cavities, a hollow block arranged within one of said chills and having its cavity in communication with said molding cavities, and a core arranged in the other chill and extending into the mold cavities and said block cavity, said core being provided with a gate leading to said chill-cavities and a trap to prevent the passage of the dross into said chill-cavities.

NATHANIEL K. B. PATCH. Witness:

NOAH F. YOUNG. 

